A simplified explicit FDTD model for dispersive Kerr media

The finite-difference time-domain (FDTD) method is widely used to solve Maxwell’s equations, but most commercial and research-grade FDTD software relies on implicit iterative solvers to handle optical nonlinearities—a computationally demanding process. Recent advances introduced an explicit FDTD approach for dispersive media with optical nonlinearities, based on a nonlinear generalization of the Lorentz dispersion model [1]. In this work, we present a simplified explicit implementation of the generalized Lorentz model in the weakly dispersive limit (ω ≪ ω₀), specifically designed for transparent Kerr media. We achieve an efficient and scalable framework for simulating the generalized nonlinear Schrödinger equation in complex structures, such as stratified media. We validate this method through two applications: the propagation of femtosecond pulses in silicon and the behavior of a Kerr Gires–Tournois interferometer, a promising platform for generating Kerr frequency combs. [1] C. Varin et al., Computer Physics Communications, 222, (2018)